Chemical composition and minerals in pyrite ash of an abandoned sulphuric acid production plant

Abstract

The extraction of sulphur produces a hematite-rich waste, known as roasted pyrite ash, which contains significant amounts of environmentally sensitive elements in variable concentrations and modes of occurrence. Whilst the mineralogy of roasted pyrite ash associated with iron or copper mining has been studied, as this is the main source of sulphur worldwide, the mineralogy, and more importantly, the characterization of nanoparticles, in coal-derived roasted pyrite ash remain to be resolved. In this work we provide essential data on the chemical composition and nanomineralogical assemblage of roasted pyrite ash. XRD, HR-TEM and FE-SEM were used to identify a large variety of minerals of anthropogenic origin. These phases result from highly complex chemical reactions occurring during the processing of coal pyrite of southern Brazil for sulphur extraction and further manufacture of sulphuric acid. Iron-rich nanoparticles within the ash may contain high proportions of toxic elements such as As, 2 Se, U, among others. A number of elements, such as As, Cr, Cu, Co, La, Mn, Ni, Pb, Sb, Se, Sr, Ti, Zn, and Zr, were found to be present in individual nanoparticles and nanominerals (e.g. oxides, sulphates, clays) in concentrations up to 5%. The study of nanominerals in roasted pyrite ash from coal rejects is important to develop an understanding on the nature of this by-product, and to assess the interaction between emitted nanominerals, ultra-fine particles, and atmospheric gases, rain or body fluids, and thus to evaluate the environmental and health impacts of pyrite ash materials.

Insights into a 20-ha multi-contaminated brownfield megasite: An environmental forensics approach

“…2). Given all the preceding considerations and the existing literature about pyrite ashes (Lin and Qvarfort, 1996;Yang et al, 2009;Oliveira et al, 2012), we addressed the behaviour of this sort of waste.…”

A preliminary evaluation of volcanic rock powder for application in agriculture as soil a remineralizer

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Quantification of inorganic arsenic exposure and cancer risk via consumption of vegetables in southern selected districts of Pakistan

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